Many construction, road building and related endeavors employ compactor machines to compact work material such as earth, asphalt, gravel, mixtures, etc. so that the work material will be suitable for an end purpose. Compaction may also be used to reduce the volume of work material, as in the case of materials such as landfill trash. A traditional approach to compacting work material in a given work area is to pass a compactor machine uniformly across the work area, using operator judgment, ground-based visual markers, or electronic positioning systems to indicate the progress of compacting the work material. Such conventional strategies typically assume that uniform coverage of a work area with a compactor machine will result in uniform compaction of the work material. Many sophisticated compacting machines, systems and operating methods have been developed over the years in an attempt to optimize operating efficiency and avoid unnecessary travel of the compactor machine across regions already covered. Despite such improvements, operating compacting machinery remains an often expensive, unpredictable and labor-intensive process.
Approaches relying upon operator judgment and perception, and even visual cues such as markers placed about the work area, have the potential for human error as well as requiring substantial operator or technician preparation time. It is common for regions to be covered by a compactor machine more or fewer times than necessary in conventional approaches, wasting time and energy, and ultimately limiting work progress. As alluded to above, in more recent years relatively sophisticated compacting systems have been developed which utilize position signals from a source such as global positioning system satellites or ground-based laser positioning systems. Certain of these systems have provided substantial improvements over traditional approaches to compactor machine guidance.
Even the most advanced systems currently available, however, generally assume that compaction progress is closely correlated with compactor coverage. In other words, while more sophisticated electronic control and positioning systems can provide for more accurate information regarding the position of a compactor and, hence, its coverage of a given work area, they do not address irregularities, or general unpredictability in the work material's compaction response. Because different regions of a work area may exhibit varying work material compaction responses, there are limitations to uniform coverage approaches, regardless of the extent of positioning accuracy and precision.
In the context of asphalt compaction, variations in compaction progress among uniformly covered regions of a work area has been recognized by Sandstrom in U.S. Pat. No. 5,942,679. In Sandstrom's approach, a compactor machine is equipped with a variety of sensors, including temperature, compactor velocity, path changes and static mode versus vibratory mode detectors. A microprocessor in Sandstrom determines a position of the compactor machine in relation to a paving machine, and hence can associate certain of the sensed operating parameters with particular regions of an area being paved.
Sandstrom purports to integrate the sensed parameters into a compaction index number representative of a total amount of compacting work the compacting machine has performed in a particular area. Although Sandstrom may have provided a useful insight, the approach does little, if anything, to guide decision-making based on the data. In other words, while Sandstrom may be useful in gathering data, Sandstrom does not teach acting upon the data apart from the conclusions of a human operator or manager. Moreover, Sandstrom does not recognize certain characteristics of work material compaction response that may be useful in planning subsequent compactor work.
As discussed above, there have been various improvements in guiding the operation of compacting machinery in recent years. In addition, certain insights have been made which relate to varying responses of work material subjected to attempted compaction. Nevertheless, there remains room for improvement.
The present disclosure is directed to one or more of the problems or shortcomings set forth above.